An organic electroluminescence (organic EL) display device includes a light-emitting element in each of a plurality of pixels, and displays an image by controlling light emission in each of the pixels individually. The light-emitting element includes a pair of electrodes, one of which is an anode electrode and the other of which is a cathode electrode, and a layer containing an organic EL material (hereinafter, referred to also as a “light-emitting layer”) held between the pair of electrodes. When electrons are injected into the light-emitting layer from the cathode electrode and holes are injected into the light-emitting layer from the anode electrode, the electrons and the holes are recombined. Extra energy released by the recombination excites, and then deexcites, light-emitting molecules in the light-emitting layer. Thus, the light-emitting elements emit light.
In such an organic EL display device, the anode electrode in each of the light-emitting elements is provided as a pixel electrode corresponding to the respective pixel, and the cathode electrode is provided as a common electrode corresponding to the plurality of pixels. The common electrode is supplied with a common potential. The organic EL display device applies a potential of the pixel electrode in each pixel with respect to the potential of the common electrode, and thus controls the light emission of each pixel.
Recently, touch panels have been widely used in electronic devices such as mobile terminals, personal computers, car navigation systems and the like. Such a touch panel is used as follows. A user touches the touch panel with his/her finger tip, a tip of a pen or the like while visually recognizing an image on a display screen of a liquid crystal display device or the like including the touch panel, and the touched position on the touch panel is detected. Thus, data is input.
For example, Japanese Laid-Open Patent Publication No. 2013-168121 discloses a touch panel. This touch panel includes a plurality of driving lines extending in a first direction, and a plurality of sensing lines extending in a second direction perpendicular to the first direction. A part of the plurality of driving lines and a part of the plurality of sensing lines are activated to perform rare scan, by which an approximate position at which the user has touched is detected. Driving lines, among the plurality of driving lines, in the vicinity of the approximate position at which the user has touched are activated, and sensing lines, among the plurality of sending lines, in the vicinity of the approximate position at which the user has touched are activated, to further perform local scan, by which a precise position at which the user has touched is detected.